Combination stepladder and vertically movable platform



W. V. EAKINS Nov. 4, 1969 COMBINATION STEPLADDER AND VERTICALLY MOVABLE PLATFORM Filed June 24, 1968 Z S Y 8 0 0 E 9 M M m m F m m 0 a EM 7 y M W goo, 6 M x J M 3 y y mi a M 5 w w 4 2 Z w H 6 United States Patent US. Cl. 182-103 6 Claims ABSTRACT OF THE DISCLOSURE A stepladder incorporating a vertically movable cargo carrying platform so supported thereon that said platform may be raised to a position above the upper extremity of the ladder, as well as lowered below the lower ends thereof when the ladder is supported on extensions.

BACKGROUND OF THE INVENTION Field of the invention A stepladder provided with a vertically movable platform which is particularly useful in raising heavy objects relative to the stepladder, to a position thereabove, as well as lowering heavy objects such as a chandelier from a ceiling to a position adjacent a floor.

Description of the prior art In the building trades, particularly in electrical and plumbing maintenance work, it is highly desirable to support a workman in an elevated position, whereby it is possible for him to control the vertical movement of a heavy object it is desired to raise or lower.

Although hoists and various types of vertically movable platforms and supports have been devised and used in the past for raising or lowering heavy objects, such devices were not adapted for use by a workman when in an elevated position. The present invention overcomes the operational disadvantages of such prior hoists and vertical-movable platforms, by supporting a workman in an elevated position, to permit the workman, when so supported, to handle a heavy object in an easy and convenient manner.

SUMMARY OF THE INVENTION A combined stepladder and vertically movable platform of relatively simple mechanical structure that is portable, and may be used to not only support a workman in an elevated position, but permits the workman, when so supported, to raise and lower heavy objects in an easy and convenient manner with a minimum of physical exertion.

A major object of the present invention is to provide a combined stepladder and vertically movable platform that is portable, can be fabricated from standard, commercially available materials, requires a minimum of maintenance attention, and may be used by a workman to climb to an elevated position, and easily and conveniently handle a heavy object when so positioned.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a side elevational view of the combined stepladder and vertically movable platform;

FIGURE 2 is a front elevational view of the device;

FIGURE 3 is a fragmentary, horizontal, cross-sectional view of the device taken on the line 33 of FIGURE FIGURE 4 is an enlarged, fragmentary, side elevational view of the vertically movable platform portion of the device;

FIGURE 5 is a vertical, fragmentary, cross-sectional "ice view of the upper portion of the device taken on the line 55 of FIGURE 2;

FIGURE 6 is an end elevation of the portion of the device shown in FIGURE 5 taken on the line 66 thereof;

FIGURE 7 is a side elevational view of the braces and extensions mounted on the lower ends thereof, and with the vertically movable platform being in a position below the lower extremities of the braces; and

FIGURE 8 is a side elevational view of the lower sprocket and a part of the endless link belt, and with a cable extending from the belt and removably connectable to either the first or second movable platform.

DESCRIPTION OF THE PREFERRED EMBODIMENT The combined stepladder and vertically movable platform A is shown in FIGURES 1 and 2., which includes two laterally spaced, upwardly extending rails 10 that support a number of horizontal rungs 12 therebetween. Two parallel, laterally spaced, upwardly extending braces 14 are oppositely situated from the rails 10. Pins 10a and 14a pivotally engage the upper ends of the rails 10 and braces 14 to secure the same to the ends of a rectangular frame 16. A rectangular, horizontal support 18 is mounted on the upper end of frame 16, as may best be seen in FIGURE 1, and conventional means B are provided for maintaining the rails 10 and the braces 14 in the spread ladder-defining position.

Each of the braces 14, as may best be seen in FIGURE 3, is of transverse, channel-shaped cross section and includes a web 20 and two flanges 22 projecting outwardly from edges thereof. A first elongate, rectangular frame C is provided that includes two side pieces 24 which are connected by cross members 26. Side pieces 24 are of channel-shaped transverse cross section and include webs 28 and flanges 30. The flanges 30 of the two Webs 28 extend outwardly away from one another. A number of longitudinaly spaced stub shafts 32 project inwardly towards one another from the adjacent faces of webs 28, as shown in FIGURES 3 and 4, and each of these shafts rotatably support a roller 34 situated within the confines of the flanges 22.

The web 20 and flanges 22 of each of the braces 14 cooperatively provide a longitudinally extending guide for one group of the rollers 32. At least three laterally spaced stub shafts 32 preferably project inwardly from each web 28 for reasons that will later be explained.

An upper sprocket 36 having pulleys 38 mounted each side thereof as shown in FIGURE 6, is rigidly secured to an upper horizontal shaft 40 (FIGURE 2) at the end of this shaft are journaled in the braces 14. The upper sprocket 36 is engaged by a downwardly extending end less link belt 42. Belt 42 engages a second lower sprocket 44 that is best shown in FIGURE 3, and is rigidly secured to a second horizontal shaft 46, the ends of which are rotatably supported in the braces 14.

A second rectangular frame D is provided that is outwardly disposed from the first frame C, as may best be seen in FIGURE 4, and is longitudinally movable relative thereto. Frame D includes two parallel, laterally spaced side pieces 48 and cross pieces 50. Legs 52 extend from the ends of side pieces 48 towards the first frame C. Stub shafts 54 project from legs 52 towards the side pieces 24, as shown in FIGURE 3. The stub shafts 54 rotatably support rollers 56 which engage the side pieces 24 of the first frame C, as shown in FIGURE 3 and are guided thereby.

Two cables 58 on first ends 58a thereof are attached to opposite sides of the belt 42, as illustrated in FIG- URE 5 by pins 42a. The second ends 58b of the cables 58 are removably attached by conventional means to 3 either the first frame C or the second frame D adjacent to the lower end thereof (FIGURE 8).

As the first frame C is moved upwardly on braces 14 by use of belt 42, the cables 58 may engage the pulleys 38. After the cables 58 are in full engagement with pulleys 38 (FIGURE the portions of the cables adjacent the ends 58a thereof move downwardly during continued rotation of the upper sprocket 36 in a counter clockwise direction. Continued movement of the belt 42 after the cables 58 are in full engagement with pulleys 38 causes the first frame C to be raised partially above the support 18.

Extensions b and 14b respectively may be afiixed by conventional means to the lower ends of rails 10 and braces 14 (FIGURE 1) when the ladder A is of insufiicient height to dispose the support 18 at a desired elevation. The cables 58 permit the first frame C to be lowered to a position, such as shown in FIGURE 7, where the frame is partially below the lower extremities of the rails 10 and braces 14. When the first frame C is to be disposed partially above the support 18 or partially below the extremities of the rails and braces, a suflicient number of pairs of rollers 34 must be provided on first frame C that at least two pairs thereof remain in engagement with the braces 14. Such engagement of the rollers 34 is required to maintain the first frame C in an aligned stable position relative to the braces 14.

A transversely positioned shaft 60 is rotatably supported under support 18 by bearings 62, as best seen in FIGURE 5. Shaft 60 includes a worm gear 64 that engages a gear 66 rigidly secured to upper shaft 40 as illustrated in FIGURE 6. The transverse shaft 60 is provided with a handle 68 or other means for rotating the same as shown in FIGURE 1. Second frame D serves to support a cargo carrying platform E, as shown in FIG- URES 1, 4 and 7. Platform E is preferably defined by a rectangular plate 70 that is transversely positioned relative to second frame D and outwardly positioned therefrom. Two spaced rigid first members 72 are secured to the underside of plate 70, and are pivotally connected on their inner ends by pins 74 to side pieces 48, as illustrated in FIGURE 4. The outer ends of members 72 are pivotally connected by pins 76 to second elongate members 78, as shown in FIGURE 4.

The lower ends of members 78 are provided with pins 80 that may be removably positionable in J-slots 82 formed in side pieces 48 to maintain the platform E in the cargo carrying position (FIGURE 4). When the platform E is not in use, pins 80 may be disengaged from slots 82 to permit the platform to depend along the outer portion of second frame D. When the platform E 0ccupies this depending position, the ladder A occupies less space, which is particularly desirable in the storage of the ladder.

To prevent inadvertent displacement of a heavy object or other cargo (not shown) from the platform E, a transverse member 84 is pivotally supported by pins 86 from the outer portions of the members 72, as shown in FIG- URE 4. The member 84 may be held in an upwardly and outwardly extending position relative to plates 70 by a conventional latch mechanism 88.

Second frame D may be moved longitudinally relative to the first frame C by the mechanism F shown in FIG- URES 2 and 3. Frame C supports a longitudinally extending threaded rod 90 that is engaged by a circular nut 92 provided with teeth 94 on the outer portion thereof. Rod 90 extends upwardly through two spaced guides 96 that are secured to two of the cross pieces 50 which form a part of the second frame D (FIGURE 2).

Nut 92 is disposed between the two guides 96. Teeth 94 are engaged by a worm gear 98 on a transverse shaft 100, and this shaft is rotatably supported in two transversely spaced bearings 102 (FIGURES 2 and 3) that are secured to the two cross pieces 50 that support guides 96. A handle 104 or like means is provided on the outer end of shaft 100 for ease in rotating the same.

Operation of the invention is quite simple. When it is desired to use the ladder A, it is transported to a desired location, preferably with the rails 10 and braces 14 disposed in substantially parallel relationship, and the platform E positioned substantially parallel to the second frame D. The rails 10 and braces 14 are then placed in the expanded stepladder-defining position illustrated in FIGURE 1. If the ladder A is not of the correct height to hold the support 18 in the desired relationship with a ceiling or the like (not shown), the extensions 10b and 1412 may be secured to the lower extremities of the rails 10 and braces 14. Irrespective of whether the extensions 10b and 14b are secured to the rails 10 and braces 14, the operation of the ladder is the same.

In the event a heavy object (not shown) is to be raised on the platform E, the handle 68 is rotated to move the first frame C downwardly on the braces 14, to a position adjacent the floor. Thereafter, the handle 104 is rotated to move the second frame D downwardly relative to the first frame C to dispose the platform E in a position where the heavy object may be conveniently placed on plate 70, shown in FIGURE 4.

If the extensions 10b and 14b are secured to ladder A, portions of the first frame C may be positioned below the lower extremities of the legs 10 and braces 14. However, two of the pairs of rollers 34 must at all times be in engagement with the braces 14 to maintain the first frame C in an aligned and supported position on the braces. After the cargo has been loaded on platform E, the handle 68 is rotated in such a direction as to cause the frame C to move upwardly on braces 14 until the cargo and platform E are at a desired elevation. When a heavy object such as a chandelier (not shown) is being removed from a ceiling, the first frame C may be moved to a position where it extends partially above the support 18. Platform E may then be moved upwardly relative to first frame C to a position where plate 70 is above support 18, and the chandelier or other heavy object may rest on the plate. The first frame C, second frame D, and platform B may thereafter be lowered as a unit to position the heavy object adjacent the floor on which ladder A rests. From the above description it will be seen that the cargo supporting plate 70 may be raised above the support 18, as well as moved below the lower extremities of rails 10 and braces 14 when the latter have extensions 10b and 14b attached thereto.

I claim:

1. In combination with a stepladder of the type that includes two spaced upwardly extending rung-supporting rails, two parallel, laterally spaced, upwardly extending braces having longitudinal guides thereon, pivotal means connecting the upper ends of said rails and braces, and means for maintaining said rails and braces in a stepladder-defining position, the improvement for lifting an object on said ladder to a position thereabove, comprising:

(a) a first elongate rectangular frame positioned parallel to the exterior surface of said braces;

(b) first means on said frame for movably engaging said guides to support said frame from said braces and permit said frame to be moved to a position partially above said pivotal means;

(c) upper and lower sprockets rotatably supported between said braces;

(d) pulley means supported in the upper portion of said braces;

(e) a second frame positioned parallel to the exterior surface of said first frame;

(f) second means for movably supporting said second frame on said first frame;

(g) third means for longitudinally moving said second frame relative to said first frame and supporting said second frame at a desired position on said first frame;

(h) an endless link belt supported on said first and second sprockets;

(i) fourth means for rotating said first and second sprockets to move said belt;

(j) a cable removably connected on a first end either to the bottom of said second frame or to said first frame intermediate the top and bottom thereof in such a manner that said cable can engage said pulley means and when connected to said first frame raise said first frame partially above said pivotal means; and

(k) a substantially horizontal platform supported from said second frame for vertically moving said object where supported thereon when either said first frame is moved relative to said braces or when said second frame is moved longitudinally relative to said first frame.

2. A stepladder as defined in claim 1 which further includes:

(1) a plurality of extensions disposed below the lower ends of said rails and braces, with said cable permitting said first frame to be lowered partially below said lower ends, and said platform when said first frame is so disposed being adapted to be moved to a position adjacent the surface on which said extensions rest to permit a heavy object to be placed on or removed from said platform.

3. A stepladder as defined in claim 1 wherein said guides comprise longitudinally extending recesses defined in said braces and said first means comprise a plurality of pairs of longitudinally spaced rollers supported from said first frame that movably engage said recesses.

4. A stepladder as defined in claim 1 wherein said first frame includes two side pieces of channel-shaped transverse cross section, and said second means comprise a plurality of pairs of rollers rotatably supported on said second frame that movably engage said side pieces.

5. A stepladder as defined in claim 1 wherein said third means further includes:

(1) a threaded rod supported in a fixed longitudinally extending position on said first frame;

(in) a circular nut rotatably supported at a fixed longitudinal position on said second frame, with said nut threadedly engaging said rod, and said nut having teeth on the external surface thereof;

(n) a worm gear rotatably supported from said second frame, which worm gear is in engagement with said teeth; and

(o) handle means for manually rotating said worm gear to move said second frame and platform longitudinally relative to said first frame.

6. A stepladder as defined in claim 1 wherein said fourth means further includes:

(1) a horizontal shaft rotatably supported from said braces, which shaft has said upper sprocket rigidly secured thereto;

(In) a gear rigidly secured to said shaft;

(n) a second shaft rotatably supported from said stepladder adjacent said gear;

(o) a worm gear rigidly secured to said second shaft, which Worm gear is in engagement with said gear; and

(p) means for rotating said second shaft.

References Cited UNITED STATES PATENTS 107,225 9/1870 Claflin 182-103 444,280 1/1891 Pepin 182-103 519,234 5/1894 Cardarelli 182-103 767,244 8/ 1904 Rieg 182-103 952,836 3/1910 McCombie 182-103 2,714,434 8/1955 Peterson 182-103 3,081,839 3/1963 OBrien 182-103 FOREIGN PATENTS 601,962 2/1960 Italy.

REINALDO P. MACHADO, Primary Examiner U.S. C1. X.R. 

